And Mewtwo's BST (Base Stat Total) is 80 higher than any of Deoxys's forms. Mewtwo: 680, Deoxys: 600. However, the different forms of Deoxys could definitely handle a Mewtwo, depending on moveset, EVs, IVs, etc... But a Mewtwo could hold his own. All in all...

Its the deoxy virus from deviant art where the author orginaly did all his work, its a series of some awsome artwork and the one below is my favorite. To check out his work head here
esepibe.deviantart.com